1. Field of the Invention
The present invention relates to a method of producing a substrate plate for a liquid crystal cell with black matrix areas. Such black matrix areas are indeed preferably arranged in places where the substrate plate is free of electrode areas.
2. Description of the Prior Art
Black matrix areas have hitherto been applied by means of one of two known methods. One of these methods is a photolithographic method, while the other is a printing method.
Both methods commence by producing structured electrode areas. To this end
a photosensitive resist is first applied to a segmental plate provided with an electrode layer; PA1 this photosensitive resist is then exposed to light through a mask; PA1 the exposed photosensitive resist is developed and PA1 the electrode layer is then etched away at the point where the photosensitive resist has been removed. PA1 a blackened polymer material is deposited on the entire substrate surface with the electrode areas and the photosensitive resist areas; PA1 the blackened polymer material is hardened, and PA1 the still remaining areas of photosensitive resist are removed, together with the blackened polymer material deposited on them, so that such blackened polymer material will remain only in the areas between the electrode areas.
In both the known methods the next processing step consists of removing the remaining photosensitive resist. In the photolithographic method this is followed by depositing a layer of blackened polymer material on the entire substrate surface with the electrode areas and then applying a photosensitive resist to this blackened layer. Subsequently, a mask is carefully and accurately aligned with respect to the electrode areas to ensure that, following exposure, the photosensitive resist can be developed in such a way as to permit the removal of those parts of the blackened layer that are underlain by the electrode areas. Blackened material will therefore remain only between the electrode areas.
In the printing method, on the other hand, the aforementioned removal of the remaining photosensitive resist is followed by carefully and accurately aligning a printing device with respect to the electrode areas, this being done in such a way that the subsequent printing will deposit blackened polymer material only in the interstices between electrode areas. The printed material is then hardened.
It is quite obvious that in both the known methods considerable costs are incurred in order to ensure accurate alignment of the exposure mask and/or the printing device with respect to the electrode areas.